The present invention relates to an electronic timepiece which has storage means storing the positions of the pointers and controls the drive of the pointers.
It is known that conventional electronic timepiece has means for storing the positions of pointers and means for providing control of the drive of the pointers and realize an electronic timepiece circuit system by a CPU core, a memory, and a peripheral pointer drive control circuit, as disclosed, for example in patent Laid-Open No. JP-A-77679/1990.
In these electronic timepieces, the presently displayed positions of the pointers used for display are stored in the storage means. The difference between the stored data about the presently displayed positions and the data about the positions to be displayed next is calculated. The pointers are driven according to the result of the calculation. This data about the displayed positions indicates positions relative to a reference position. Therefore, an initializing means for setting the reference position has been needed.
The pointer position storage means of the prior art electronic timepiece circuit system uses a static RAM as a data memory, the static RAM being a volatile memory. This static RAM is memory means adapted for electronic timepiece circuits, because the RAM and other circuit elements can be fabricated easily by the same process, and because the RAM consumes only a small amount of electric power.
However, this memory means has the disadvantage that it cannot retain data when the supply of electrical current is interrupted. As in the conventional instrument, even if data about the positions of the pointers are stored, data about the previous positions of the pointers are not stored when the electric battery is exchanged. Therefore, whenever such an exchange is executed, the initializing means must reset the reference position for the pointers.
When the battery is exchanged, the pointers display random positions. Much labor and long time are needed to drive the pointers by a switch means or the like in doing after-sale service.